rtcom

Rust Terminal Communication — a modern, safe, cross-platform serial terminal for embedded and hardware engineers. Written in Rust, aiming for feature parity with tio while adding a native Windows backend, a first-class library API, and a pluggable architecture for future protocol decoding, scripting, and network sharing.

Features (v0.1)

Async serial I/O built on tokio-serial (Linux / macOS / BSD).
UUCP-style lock files so two rtcom instances cannot race the same device.
Interactive command key (^A by default, configurable via --escape) with: ?/h help, ^Q/^X quit (picocom convention), c show config, t/g toggle DTR/RTS, \ send break, b<rate><Enter> change baud rate.
CR/LF mappers (--omap / --imap / --emap) following picocom's crlf / lfcr / igncr / ignlf rule names.
Clean shutdown on SIGINT / SIGTERM / SIGHUP (termios restored, lock file removed, exit code 128 + signum).
Structured diagnostics via tracing (honours RUST_LOG; -v / -vv / -vvv raises the default level).
End-to-end tests via socat-allocated pseudo-terminals — the full pipeline is regression-guarded.

Quick start

# Connect to a USB-serial dongle at 115200 8N1 (default)
rtcom /dev/ttyUSB0

# Change baud + parity + enable LF->CRLF on send
rtcom /dev/ttyUSB0 -b 9600 -p even --omap crlf

# Print the full option list
rtcom --help

Installation

From crates.io

cargo install rtcom-cli --locked

--locked pins the dependency versions shipped in Cargo.lock, which keeps the MSRV contract (Rust 1.85) honest.

From source

git clone https://github.com/TrekMax/rtcom
cd rtcom
cargo install --path crates/rtcom-cli --locked

On Linux you'll need libudev-dev (or the equivalent package on your distro) for the underlying serialport crate.

Pre-built binaries

Each tagged release publishes pre-built binaries for the major platforms — grab one from GitHub Releases:

Platform	Architecture	Asset
Linux	x86_64	`rtcom-x86_64-unknown-linux-gnu`
Linux	aarch64	`rtcom-aarch64-unknown-linux-gnu`
macOS	Intel	`rtcom-x86_64-apple-darwin`
macOS	Apple Silicon	`rtcom-aarch64-apple-darwin`
macOS	Universal	`rtcom-universal-apple-darwin`
Windows	x86_64	`rtcom-x86_64-pc-windows-msvc.exe`

Each release also ships a checksums-sha256.txt so you can verify the download.

Distribution packages

Homebrew tap, AUR, and winget packages are planned for v0.2+. In the meantime, cargo install or the GitHub Releases tarball is the canonical path.

Command keys

Once a session is running, the escape key (default ^A = Ctrl-A; override with --escape '^T' etc.) puts the parser into command mode. The next byte is matched against this table; unknown keys silently return to default mode.

Key	Action
`?` or `h`	Print the command-key cheatsheet
`^Q` or `^X`	Quit the session cleanly (Ctrl-Q / Ctrl-X)
`c`	Show current serial configuration
`t`	Toggle DTR
`g`	Toggle RTS
`\`	Send a 250 ms line break
`b<rate><Enter>`	Change baud rate (e.g. `^A b 115200 <Enter>`)
The escape key again	Send the escape byte verbatim to the wire
`Esc`	Cancel command mode, return to default

vs. picocom / tio

Capability	picocom	tio	rtcom (v0.1)
Async I/O (`tokio`)	❌	❌	✅
UUCP lock files	✅	✅	✅
Raw-mode cleanup on any exit path	⚠️	⚠️	✅
CR/LF omap/imap/emap	✅	❌	✅
`^A <key>` command parser	✅	✅	✅
Library API (`rtcom-core`)	❌	❌	✅
Native Windows backend	❌	❌	🚧 v0.8
Structured logging / `tracing`	❌	❌	✅
Built-in xmodem / ymodem	❌	❌	🚧 v0.6

🚧 = on the roadmap.

Workspace layout

Crate	Role
`rtcom-core`	Serial device trait, event bus, session orchestrator, mappers, UUCP lock (library)
`rtcom-cli`	`rtcom` binary: argument parsing, TTY setup, signal handling, main loop

Architecture

Event-driven, single-task Session wired through a tokio::broadcast bus. See docs/architecture.svg and the CLAUDE.md design document for the full rationale.

Contributing

The development plan is maintained in CLAUDE.md; §8 covers the TDD + commit-per-phase workflow the project enforces, §9 the coding conventions. Bug reports and PRs welcome — please open an issue to discuss larger changes before sending code.

Running the full test suite locally:

cargo fmt --all -- --check
cargo clippy --workspace --all-targets --all-features -- -D warnings
cargo test --workspace --all-features

License

Apache-2.0. See LICENSE.

rtcom-core 0.1.1